Technical Field
[0001] The present invention relates, in general, to variable apparatuses for separating
oil from blow-by gas in engines and, more particularly, to a variable apparatus, which
is installed in a baffle compartment of a cylinder head cover of an engine to separate
oil from blow-by gas generated in the engine.
Background Art
[0002] As well known to those skilled in the art, while an engine is running, combustion
gas and unburned gas, which are generated in the explosion stroke of the engine, leak
into a crankcase through a fine gap between a piston and a cylinder liner. This gas
is called "blow-by gas".
[0003] The blow-by gas, which is drawn into the crankcase, is guided to a cylinder head
cover, which is disposed on top of the cylinder head of the engine. The blow-by gas,
which is guided to the cylinder head cover, is then guided to an intake system of
the engine and is thus reburned.
[0004] However, during this process, oil mixes with the blow-by gas. As the amount of oil
that mixes with the blow-by gas is increased, the consumption rate of oil in the engine
increases, the durability of the engine is deteriorated, and the amount of harmful
exhaust gas is increased. As such, many problems are caused.
DE 20 2004 009 673 U1 refers to a valve assembly for deaerating of a crankcase showing same constructional
features as defined in the preamble of claim 1.
[0005] To solve the above-mentioned problems, an oil separating apparatus, which is provided
on the path in the cylinder head along which the blow-by gas travels, was proposed.
Disclosure of Invention
Technical Problem
[0006] As shown in FIG. 1, in the conventional apparatus for separating oil from blow-by
gas, an inlet 2 and an outlet 3 for blow-by gas are formed in a baffle compartment
1. Furthermore, several partition walls 4 are alternately disposed in the baffle compartment
1 such that the path along which blow-by gas passes has a zigzag structure. Thus,
oil contained in blow-by gas falls due to its own weight or sticks to the partition
walls 4. Thereafter, the separated oil is discharged through a separate oil discharge
passage (not shown).
[0007] However, the conventional fixed-type oil separating apparatus having the stationary
partition walls is problematic in that the efficiency with which oil is separated
from blow-by gas varies depending on the speed at which blow-by gas passes through
the baffle compartment 1, that is, depending on the conditions in the engine.
[0008] In an effort to overcome the problems experienced with the conventional art, an apparatus
for separating oil from blow-by gas, which includes movable impactors, which are rotatably
provided around an inlet and an outlet of a baffle compartment, an actuator for rotating
the movable impactors, and a controller that operates the actuator depending on the
operation conditions of the engine, was proposed in Korean Patent Laid-open Publication
No.
2005-0045330. However, the variable oil separating apparatus has problems in that, because several
separate electric components, such as the actuator, the controller and a sensor for
detecting the operation conditions of the engine, are required, the manufacturing
costs are increased, and, when taking high-temperature and high-pressure conditions
of the engine into account, the reliability and durability of the actuator and controller
are markedly reduced.
[0009] Furthermore, it is very difficult to quickly control the actuator in response to
the operation conditions of the engine, which vary rapidly depending on the driving
conditions of the vehicle. In addition, when the engine is operated at high speed,
the pressure of blow-by gas is increased and the flow rate thereof is thus increased.
Then, the load of the actuator is also increased. Therefore, there is a disadvantage
in that an actuator having high capacity is required.
[0010] Moreover, the movable impactor has a hinged door structure, that is, it is too simple.
Therefore, because the contact area between the movable impactor and blow-by gas,
which passes through the movable impactor, is relatively small, the oil separating
function is not reliably conducted. As well, the shape of the contact surface is fixed
rather than changing depending on the pressure of blow-by gas. As a result, there
is a problem in that, when the engine is operating at high speed, the oil separating
ability is reduced.
Technical Solution
[0011] Accordingly, the present invention has been made keeping in mind the above problems
occurring in the prior art, and an object of the present invention is to provide a
variable apparatus for separating oil from blow-by gas in an engine in which, when
the engine is operating at low speed, relatively low negative pressure is applied
to blow-by gas, and, when the engine is operating at high speed, the amount of negative
pressure applied to blow-by gas is increased in order to actively respond to the speed
at which blow-by gas flows, thus having markedly enhanced ability to separate oil
from blow-by gas even when operating at high speed.
[0012] Another object of the present invention is to provide a variable apparatus for separating
oil from blow-by gas in an engine in which, in the case where the ability to separate
oil from the blow-by gas is reduced when the flow speed of blow-by gas is low, blow-by
gas is accelerated and rotated to enhance the oil separating ability and the pressure
in a crankcase is prevented from becoming positive pressure by reducing a difference
in pressure, and in which, when the engine is operating at high speed, the area of
the partition wall that contacts blow-by gas is increased to enhance the oil separating
ability and the difference in pressure is increased such that the pressure in the
crankcase can fall within a desired range.
Advantageous Effects
[0013] The present invention provides a variable apparatus for separating oil from blow-by
gas in an engine which appropriately responds to the speed at which blow-by gas flows,
so that the efficiency of separation of oil from blow-by gas can be increased even
when the blow-by gas flows at a high speed. Furthermore, in the present invention,
because an elastic member having a spiral shape has a simple structure and the number
of parts is reduced, the reliability of the assembled apparatus is enhanced, the cost
of manufacturing the apparatus is reduced, and the durability thereof is markedly
enhanced. In addition, in response to the pressure of blow-by gas, the elastic member
extends or contracts and thus guides the rotary flow of blow-by gas and, simultaneously,
the shape of the contact surface with the blow-by gas is changed, so that the ability
to separate oil from blow-by gas can be increased.
Brief Description of the Drawings
[0014] FIG. 1 is a schematic view showing a conventional apparatus for separating oil from
blow-by gas in an engine;
[0015] FIG. 2 is a sectional view showing a part of a variable apparatus for separating
oil from blow-by gas in an engine which is not in a varied state;
[0016] FIG. 3 is a sectional view showing the part of the variable apparatus of FIG. 2 which
is operating at low speed;
[0017] FIG. 4 is a sectional view showing the part of the variable apparatus of FIG. 2 which
is operating at high speed;
[0018] FIG. 5 is a perspective view of FIG. 4;
[0019] FIG. 6 is a schematic view showing an example of a baffle compartment in which variable
apparatuses for separating oil from blow-by gas are installed;
[0020] FIG. 7 is a view corresponding to FIG. 6, but showing another example of a baffle
compartment in which variable apparatuses for separating oil from blow-by gas are
installed;
[0021] FIGS. 8 through 10 are perspective views showing a process of varying a variable
apparatus for separating oil from blow-by gas in an engine, according to the present
invention; and
[0022] FIGS. 11 and 12 are schematic views showing examples of installation of variable
apparatuses for separating oil from blow-by gas in a baffle compartment of the engine
according to the present invention.
Best Mode for Carrying Out the Invention
[0023] Hereinafter, variable apparatuses for separating oil from blow-by gas in engines
according to a preferred embodiment of the present invention will be described in
detail with reference to the attached drawings.
[0024] As shown in FIG. 2, a variable apparatus for separating oil from blow-by gas in an
engine is installed in a baffle compartment of a cylinder head cover of the engine,
and includes a partition wall 10, a cover 20 and a plurality of elastic members 30.
[0025] Here, the partition wall 10 has a blow-by gas passing hole 10a therein. The single
partition wall 10 may be provided in the baffle compartment 11. Alternatively, as
shown in FIG. 6, several partition walls 10 may be provided in the baffle compartment
11.
[0026] Furthermore, as shown in FIG. 2, the cover 20 has a shape corresponding to that of
the passing hole 10a to close the passing hole 10a. Preferably, the shape and size
of the cover 20 are optimally determined such that the cover 20 is appropriately moved
away from the passing hole 10a of the partition wall 10 depending on the change in
pressure of blow-by gas while the engine is operated at low speed or at high speed.
[0027] That is, the pressure of blow-by gas, which is applied to the cover 20, pertains
to the area of the cover 20. The area of the cover 20 can be optimized through testing.
[0028] Meanwhile, the elastic members 30 are interposed between the partition wall 10 and
the cover 20 and are made of elastic material which can be changed in shape such that
the cover 20 is moved away from the partition wall 10 by a predetermined distance
depending on the pressure of blow-by gas supplied from the engine, and passages are
thus defined.
[0029] Particularly, in this example, as shown in FIGS. 3, 4 and 5, each elastic member
30 is a spiral elastic plate, which has a surface twisted into a spiral having a predetermined
angle, so that, when the elastic member 30 is elastically extended, blow-by gas is
spirally moved under the guidance of the elastic member 30.
[0030] As shown in FIGS. 2 through 5, two elastic members 30 may be symmetrically provided
at opposite sides of the passing hole 10a of the partition wall 10. Alternatively,
three, four, five or more elastic members 30 may be provided around a single passing
hole 10a.
[0031] Particularly, in this example, the angle at which the elastic member 30 is twisted
and the number of twists of the elastic member 30 may be variously changed. Furthermore,
several elastic members 30 may be installed parallel to each other around the passing
hole 10a.
[0032] Here, the elasticity of the elastic member 30 can be also optimally designed through
testing.
[0033] In FIG. 5, although the elastic member 30 is illustrated as being twisted once, it
may be twisted two or more times.
[0034] The operation of the variable apparatus for separating oil from blow-by gas in the
engine will be explained herein below. As shown in FIG. 2, when the engine is in a
stopped state or in a lowest-speed state, because the speed at which blow-by gas flows
is zero or minimual, the cover 20 closes the passing hole 10a of the partition wall
10, or leaves it slightly open. Thus, the function of separating oil using the weight
of the oil is smoothly conducted.
[0035] As shown in FIG. 3, when the engine is operating at low speed, because blow-by gas
flows at low speed, the cover 20, to which the pressure of the blow-by gas is applied,
is spaced apart from the passing hole 10a by a relatively short distance. At this
time, the speed at which blow-by gas flows is increased, so that, even when the engine
is running at a low speed, the oil separating function can be reliably conducted.
[0036] As shown in FIGS. 4 and 5, when the engine is operating at high speed, because the
amount of blow-by gas is increased, blow-by gas flows at high speed. Therefore, the
blow-by gas is applied to the cover 20 at high pressure, so that the cover 20 is spaced
apart from the passing hole 10a of the partition wall 10 by the maximum distance.
At this time, the speed at which blow-by gas flows is maximized, so that, even when
the engine is running at a high speed, the oil separating function can be reliably
conducted.
[0037] Here, as the speed of the engine is increased from FIG. 2 to FIG. 4 through FIG.
3, the length of the passage along which blow-by gas contacts the elastic members
30 is increased and, simultaneously, rotary flow of the blow-by gas is induced, thus
reliably conducting the oil separating function.
[0038] Therefore, the variable apparatus for separating oil from blow-by gas can reliably
conduct the variable oil separating function using the elastic members 30 having simple
structures even without having a separate actuator or controller, unlike the conventional
art. Furthermore, because the length of the passage along which the blow-by gas contacts
the elastic members 30 is variable, the oil separating ability can be markedly increased.
[0039] Meanwhile, FIG. 6 is a schematic view showing an example of a baffle compartment
11 in which variable apparatuses for separating oil from blow-by gas are installed.
[0040] As shown in FIG. 6, several partition walls 10 may be provided in the baffle compartment
11. One or at least two covers 20 and elastic members 30 may be installed in each
partition wall 10.
[0041] Therefore, blow-by gas, which is drawn into the baffle compartment 11 through an
inlet 12, passes through the several passing holes 10a of the partition walls 10.
During this process, oil is separated from the blow-by gas both by the elastic members
30 and by the covers 20. Thereafter, the blow-by gas is supplied into the intake system
of the engine through an outlet 13 of the baffle compartment 11.
[0042] Here, the design of the numbers and the positions of the partition walls 10, the
covers 20 and the elastic members 30 may be variously changed depending on the outflow
rate of blow-by gas, the shape of the baffle compartment 11, and the characteristics
of the engine.
[0043] For example, as shown in FIG. 7, partition walls 10 may be constructed in a baffle
compartment 11 in the same manner as that of the partition walls 4 of the conventional
baffle compartment 1 of FIG. 1. The covers 20 and the elastic members 30 of the present
invention are installed in such partition walls 10. This variable apparatus for separating
oil from blow-by gas is constructed such that the covers 20 maintain the closed state
when the engine is operating at low speed, and only when the engine is operating at
high speed are the covers 20 opened. When the engine is running at a low speed, even
though the covers 20 are closed, because the amount of blow-by gas is relatively small,
blow-by gas can sufficiently pass through the space defined between the partition
walls 10, and oil can be reliably separated from the blow-by gas.
[0044] When the engine is running at a high speed, the amount of blow-by gas is increased.
In response to this, the covers 20 are opened, so that blow-by gas passes through
the space defined between the partition walls and, simultaneously, passes through
the passing holes 10a, which form bypass passages. Therefore, oil can be reliably
separated from the blow-by gas.
[0046] The operation of the second embodiment of the present invention for increasing the
oil separation efficiency is conducted in a manner opposite to that of the example
above.
[0047] In detail, in the case of the example described above, when blow-by gas flows at
low speed, oil is separated from the blow-by gas by its own weight. However, depending
on changes in parameters, such as the operating conditions of the vehicle, the kind
of oil and the characteristics of the engine, the case in which, when blow-by gas
flows at low speed, oil is not as easily separated from the blow-by gas as when the
blow-by gas flows at high speed, may arise.
[0048] The embodiment makes it possible to easily separate oil from blow-by gas even in
the above-mentioned case.
[0049] Hereinafter, the embodiment of the present invention will be described in detail
with reference to FIGS. 8 through 10.
[0050] As shown in FIG. 8, the general construction of the embodiment is similar to that
of the example above. However, unlike the example above, in which, when the pressure
of blow-by gas is increased, that is, when the engine is operating at high speed,
the cover 20 that closes the passing hole 10a under normal conditions is spaced apart
from the passing hole 10a, and in which, when the pressure of blow-by gas is reduced,
that is, when the engine enters the low-speed state, the cover 20 is returned to its
original state by the elasticity of the elastic members 30, in the second embodiment,
when blow-by gas flows at low speed, the cover 20 maintains its position spaced apart
from a passing hole 10a, when blow-by gas flows at high speed, the cover 20 closes
the passing hole 10a, and when blow-by gas flows at low speed again, the cover 20
is returned to its original state, that is, to the spaced apart position, by the elasticity
of elastic members 40.
[0051] That is, the elastic member 40 of the embodiment is biased in the opposite direction
as the elastic member 30 of the example above.
[0052] In the embodiment having the above-mentioned construction, when operating at low
speed, blow-by gas is rotated and accelerated while passing through the passing holes
10a of the partition walls 10 and between the partition walls 10, thereby the efficiency
at which oil is separated from blow-by gas is increased.
[0053] The well-known phenomenon stating that fluid flowing in a large flow area increases
in speed when entering a small flow area is known as Bernoulli's theorem.
[0054] In other words, when blow-by gas that flows in a large flow area passes through the
relatively narrow passage defined between the cover 20 and the passing hole 10a, the
speed of the blow-by gas is increased. Thanks to this principle, even in the condition
in which oil is not easily separated from blow-by gas when the engine is operating
at low speed, this embodiment can achieve the purpose of increasing the efficiency
at which oil is separated from blow-by gas.
[0055] Meanwhile, each elastic member 40 has a shape such that it is twisted into a spiral
having a predetermined angle. The elastic member 40 serves to spirally otate and accelerate
blow-by gas. Therefore, in the same manner as the example above, the efficiency at
which oil is separated from blow-by gas is further increased by the increased speed
and rotation of blow-by gas.
[0056] Flow guides 41, which guide the flow of blow-by gas, protrude from the elasticity
member 40, so that, when blow-by gas flows along the flow guides 41, the rotation
thereof is further accelerated.
[0057] As describe above, in the second embodiment, blow-by gas, which flows at low speed,
is rotated and accelerated by the elastic members 40, which elastically maintain the
distance between the cover 20 and the blow-by gas hole 10a, thus increasing the efficiency
at which oil is separated from blow-by gas. Hereinafter, the fact, in which, even
when blow-by gas flows at high speed, the efficiency at which oil is separated from
blow-by gas can be increased in response to this, will be explained.
[0058] As shown in FIGS. 9 and 10, when blow-by gas flows at high speed, the pressure at
which blow-by gas pushes the cover 20 increases. When high-speed blow-by gas overcomes
the elasticity of the elastic members 40, which space the cover 20 apart from the
passing hole 10a, the cover 20 is moved by the pressure of the blow-by gas towards
the passing hole 10a and thus closes the passing hole 10a. FIG. 9 illustrates the
cover 20 moved towards the passing hole 10a by blow-by gas, the flow speed of which
is increased. FIG. 10 illustrates the passing hole 10a, which is completely covered
with the cover 20 by the increased pressure of the blow-by gas.
[0059] Thanks to this structure, even when blow-by gas flows at high speed, the efficiency
at which oil is separated from blow-by gas can be increased.
[0060] In detail, when blow-by gas strikes the cover 20 at high speed, the cover 20 moves
towards the passing hole 10a and closes it. Then, the area of the partition wall 10
that is struck by the blow-by gas is increased. As a result, the oil separating efficiency
is increased by the increased area of the partition wall 10. Here, as the shape of
the elastic member 40 is changed, because the gap between the partition wall 10 and
the cover 20 is reduced, acceleration and rotary flow of blow-by gas are induced,
so that the oil separating efficiency can be further increased. Furthermore, during
the process in which the cover 20 is moved towards the passing hole 10a while overcoming
the elasticity of the elastic member 40, the energy of high-speed blow-by gas is reduced.
Therefore, there is an advantage in that blow-by gas is prevented from entering the
intake hole of the engine in a state in which oil is not separated from the blow-by
gas.
[0061] In other words, in the embodiment, in the case where the engine is running at a low
speed, the oil separating efficiency can be enhanced by the acceleration of blow-by
gas, and, in the case where the engine is running at a high speed, the oil separating
efficiency can be enhanced by increasing the area over which the blow-by gas strikes
the partition wall 10.
[0062] Meanwhile, in the variable apparatus of the embodiment of the present invention,
the pressure in a crankcase, into which oil separated from blow-by gas is moved, can
be controlled.
[0063] In detail, when the engine is running at a low speed, the cover 20 maintains the
state of being spaced apart from the passing hole 10a, so that the difference in the
pressure of blow-by gas is minimized.
[0064] In other words, because the negative pressure difference applied to the blow-by gas
is minimized, positive pressure is prevented from being applied to the crankcase.
[0065] Meanwhile, when the engine is running at a high speed, the difference in pressure
of blow-by gas is increased while the blow-by gas overcomes the elasticity of the
elastic member 40. This makes it possible to reduce the negative pressure applied
to the crankcase to within desired conditions, for example, a predetermined design
value.
[0066] As describe above, like the first embodiment, the variable apparatus for separating
oil from blow-by gas according to the embodiment can reliably conduct the variable
oil separating function using the elastic members 30 having simple structures, even
without a separate actuator or controller, such as that used in the conventional art.
Furthermore, because the length of the passage along which the blow-by gas contacts
the elastic members 30 is variable, the oil separating ability can be markedly increased.
[0067] Meanwhile, as shown in FIG. 11, in the embodiment, several partition walls 10 may
be provided in a baffle compartment 11, and one or at least two covers 20 and elastic
members 30 may be installed in each partition wall 10, in the same manner as in the
first embodiment.
[0068] Therefore, blow-by gas, which is drawn into the baffle compartment 11 through an
inlet 12, passes through the several passing holes 10a of the partition walls 10.
During this process, oil is separated from the blow-by gas by the elastic members
30 and the covers 20. Thereafter, the blow-by gas is supplied into an intake system
of the engine through an outlet 13 of the baffle compartment 11.
[0069] Here, the design of the numbers and the positions of the partition walls 10, the
covers 20 and the elastic members 30 may be variously changed depending on the outflow
rate of the blow-by gas, the shape of the baffle compartment 11, and the characteristics
of the engine.
[0070] Furthermore, as shown in FIG. 12, as in the embodiment, partition walls 10 according
to the embodiment of the present invention may be constructed in a baffle compartment
11 in the same manner as that of the partition walls 4 of the conventional baffle
compartment 1 of FIG. 1. The covers 20 and the elastic members 30 of the embodiment
of the present invention are installed in such partition walls 10. The variable apparatus
for separating oil from blow-by gas according to the embodiment having the above-mentioned
structure is constructed such that, when the engine is operating at low speed, the
covers 20 maintain the open state, and, when the engine is operating at high speed,
the covers 20 are closed. When the engine is running at a low speed, blow-by gas is
accelerated in the state in which the covers 20 are open, thus increasing the efficiency
at which oil is separated from blow-by gas.
[0071] When the engine is running at a high speed, because blow-by gas flows at high speed,
the covers 30 are moved towards the passing holes 10a and thus close the passing holes
10a, so that the area of the partition walls 10 that is struck by the blow-by gas
is increased, thereby increasing the efficiency at which oil is separated from blow-by
gas.
Industrial Applicability
[0072] As described above, the present invention provides a variable apparatus for separating
oil from blow-by gas in an engine which appropriately responds to the speed at which
blow-by gas flows, so that the efficiency of separation of oil from blow-by gas can
be increased even when the blow-by gas flows at a high speed. Furthermore, in the
present invention, because an elastic member having a spiral shape has a simple structure
and the number of parts is reduced, the reliability of the assembled apparatus is
enhanced, the cost of manufacturing the apparatus is reduced, and the durability thereof
is markedly enhanced. In addition, in response to the pressure of blow-by gas, the
elastic member extends or contracts and thus guides the rotary flow of blow-by gas
and, simultaneously, the shape of the contact surface with the blow-by gas is changed,
so that the ability to separate oil from blow-by gas can be increased.